Laboratorio de Enfermedades Infecciosas, Instituto de Medicina Preventiva Veterinaria, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Casilla P.O. Box 567, Valdivia, Chile.
Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.
Vet Microbiol. 2024 Nov;298:110251. doi: 10.1016/j.vetmic.2024.110251. Epub 2024 Sep 21.
Copper (Cu) ions have been recognized for their efficacy in inactivating bacteria, including Mycobacterium avium subsp. paratuberculosis (MAP), the causative agent of Johne's disease (JD) known for its resilience to unfavorable conditions. However, the response of MAP isolates isolated from cows to Cu exposure remains inadequately understood, as their responses may differ from those of laboratory-adapted reference strains. In this study, we examined the response of MAP isolates obtained from MAP-infected and affected cows to Cu ion treatment, comparing that with the response of the reference strain ATCC 19698 to the same treatment. Three MAP field isolates and the MAP reference strain were exposed to Cu ions, and their viability, protein/lipid damage, ROS production, and gene expression were evaluated in triplicate. Survival differed among isolates, with an isolate from a cow with clinical JD exhibiting increased tolerance to Cu exposure. While Cu treatment induced lipid peroxidation and ROS production across all isolates, genes associated with Cu detoxification and virulence were upregulated, particularly in the reference strain. Whole genome sequencing analysis revealed that, despite genomic similarities between field isolates and the reference strain ATCC 19698, there were differences regarding the presence/absence of genes related with certain virulence factors. Further research on Cu exposure with larger numbers of MAP isolates is needed to explain the stress-induced responses that influence MAP survival during natural infections and in challenging environments.
铜（Cu）离子已被证明能够有效灭活细菌，包括导致结核病（JD）的分枝杆菌副结核亚种（MAP），其对不利条件具有很强的抵抗力。然而，从奶牛中分离出的 MAP 分离株对 Cu 暴露的反应仍了解不足，因为它们的反应可能与实验室适应的参考株不同。在这项研究中，我们研究了从 MAP 感染和受影响的奶牛中分离出的 MAP 分离株对 Cu 离子处理的反应，并将其与参考株 ATCC 19698 对相同处理的反应进行了比较。将三种 MAP 田间分离株和 MAP 参考株暴露于 Cu 离子中，并在三重复验中评估了它们的生存能力、蛋白质/脂质损伤、ROS 产生和基因表达。分离株之间的存活情况存在差异，来自患有临床 JD 的奶牛的分离株对 Cu 暴露的耐受性增加。虽然 Cu 处理诱导了所有分离株的脂质过氧化和 ROS 产生，但与 Cu 解毒和毒力相关的基因被上调，特别是在参考株中。全基因组测序分析表明，尽管田间分离株和参考株 ATCC 19698 之间存在基因组相似性，但与某些毒力因子相关的基因的存在/缺失存在差异。需要对更多的 MAP 分离株进行 Cu 暴露研究，以解释影响 MAP 在自然感染和挑战性环境中存活的应激诱导反应。
